Black sulfur dye.



NITED STATES:

PATENT OFFICE.

RICHARD KIROI-II-IOFF AND EMIL HAUSSMANN, OF BERLIN, GERMANY, AS-SIGNORS TO THE AOTIEN-GESELLSOHAFT FllR ANILIN FABRIKATION,

OF SAME PLACE.

BLACK SULFUR DYE.

SPECIFICATION forming art Of Letters Patent No. 647,847, dated April 17,1900.

Application filed January 9, 1900. Serial No. 870. (No specimens.)

T0 at whom it may concern.-

Be it known that we, RICHARD KIROHHOFF and EMIL HAUSSMANN, of Berlin, inthe Kin gdom of Prussia, German Empire, have invented new and usefulImprovements in the Production of Black Dye; and we do hereby declarethat the following is a full, clear, and exact description of theinvention, which will enable others skilled in the art to which itappertains to make and use the same.

In United States Letters Patent Nos. 610,541 and 625,717 there isdescribed a black coloring-matter directly dyeing cotton which has sincebeen brought upon the market under the name of im1nedial-black. The dyeis produced by melting with sulfur and sulfids of alkali metalsdinitroiixydiphenylamin:

N 0 Os the dried and powdered melt dyeing unmordanted cotton deep blacktints without requiring a subsequent oxidation.

We have now made the discovery that by allowing sulfur and sulfids ofalkali metals to act on equimolecular mixtures ofdinitrooxydiphenylaniiu and picramic acid a new coloriug-matter isformed which dyes unmordanted cotton deep-black shades. It might havebeen expected that the reaction would lead to a mixture ofimmedial-black and of a dyestuff deriving from picramic acid; but theproperties of our new product being essentially different from those ofthe two dyestuffs above mentioned there is no doubt that a new producthas been formed which contains the residue as well of pioramic acid asof dinitrooxydiphenylamin. In compliance with this supposition it hasbeen found impossible to arrive at our new product by mixing in variousproportions the dyestulfs obtained by treatment with sulfur and sulfidsof alkalies from picramic acid and from dinitrooxydiphenylamin.

To further illustrate our invention, we give the following examples: Onehundred and seventy kilos of sodium sulfid, sixty kilos of sulfur, andfifteen kilos of water are melted together, and a mixture of twentykilos of dinitrooxydiphenylamin and 14.3 kilos of picramic acid is addedthereto at about 100 centigrade. The formation of the coloringmatterbegins after a short time, and it is completed by slowly raising thetemperature and maintaining it at least for several hours at 145.

The dyestulf can be rendered ready for technical use by several methods:Either the melt is heated up to a somewhat more elevated temperatureuntil it is perfectly dry (it is then powdered and may be directlyemployed for dyeing) or the melt is dissolved in water and thedyestulfis precipitated from the solution obtained by addition of commonsalt or of mineral acids or by the introduction of a current of air orof carbonic acid. The blue precipitate thus produced is filtered andpressed. The pressed cake is melted together with sodium sulfid on theWater-bath,

and the thick mass is brought to dryness by allowing it to stand in thedry-room or by evaporation on the water-bath. The dyestulf isolated byone of these methods dissolves in Water with deep-blue-blackcoloratiomwhich on addition of caustic-soda lye turns dark blue. Fromits aqueous solution the dyestufi is precipitated by means of commonsalt in the shape of a green -black powder. It is likewise precipitatedby mineral acids or acetic acid. It is insoluble in alcohol and hardlysoluble in concentrated sulfuric acid in the cold. On heating thedyestuff with this latter agent it dissolves, forming a dark-bluesolution, which on addition of ice-water yields a black-violetprecipitate.

The dyestuff dissolves in fuming sulfuric acid of twenty-five per cent.S0, with blackviolet coloration. From this solution ablackviolet powderseparates on addition of ice. On heating the aqueous solution of thedyestufi with caustic-soda lye and zinc-dust the color disappears. Onexposure to air, however, the colorless solution thus obtained assumesagain the dark-blue color of the original solution. The coloring-matterdyes unmordanted cotton deep-black shades.

The same dyestuffi can likewise be obtained if in the preceding examplefor picramic acid the equimolecular quantity of picric acid issubstituted, picramic acid being produced, as

l known, by he ac io of su fidso ja kali metals on picric acid duringthe melting process.

Having thus described our invention and in what manner the same can beperformed, what we claim as new is said dye being insoluble in alcohol,easily soluble in water forming a blue-black solution which on additionof caustic-soda lye turns dark blue, the dye being precipitated from itsaqueous solution by means of common I salt or mineral acids or acetlc3.016. or bya current of airor carbonic acid in the shape of agreen-black powder; being soluble in hot concentrated sulfuric acid withdark-blue coloration, in fuming sulfuric acid of twentyfive per cent. SOwith black-violet col0ra- V ti n b t Solutions yiel ng bla k-vi le p Theblack dye produced by melting with cipitates on addition of ice orice-water forming on reduction with zinc-dust and caustic- .soda lye acolorless solution which on exposure to air assumes the orignaldark-blue color of the dyestufi the new coloring-matter dyeingunmordanted cotton from a bath containing common salt deep-black shades.

In witness whereof we have hereunto signed our names, this 21st day ofDecember, 1899, in the presence of two subscribing witnesses.

RICHARD KIRGHHOFF. EMIL HAUSSMANN. Witnessesi Y a HENRY HAsPER, WOLDEMARHAUPT.

